Dihydroxy compound

ABSTRACT

The present invention provides a method for producing a thermoplastic resin by reacting reactants comprising a dihydroxy compound. In this production method, the dihydroxy compound comprises a dihydroxy compound represented by the following formula (1), wherein the total weight of a compound represented by the following formula (A), a compound represented by the following formula (B), and a compound represented by the following formula (C) in the dihydroxy compound is 1,500 ppm or less, based on 100 parts by weight of the dihydroxy compound represented by the formula (1):

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a Divisional of U.S. application Ser. No.15/769,486, filed Apr. 19, 2018, which is a National stage ofInternational Patent Application No. PCT/JP2016/082617, filed Nov. 2,2016, which claims priority to Japanese Application No. 2015-216979,filed Nov. 4, 2015. The disclosures of application Ser. No. 15/769,486and International Patent Application No. PCT/JP2016/082617 areincorporated by reference herein in their entireties.

TECHNICAL FIELD

The present invention relates to a thermoplastic resin that is excellentin dimensional stability upon molding and hue.

BACKGROUND ART

In recent years, electronic devices such as digital cameras, smartphones and tablets have become popular, and a demand for compact cameramodules has been increased. For these camera modules, plastic lenses arepreferably used, rather than glass lenses. This is because a plasticlens can be used in various forms such as a thin lens or an asphericallens, and the plastic lens is inexpensive and the mass productionthereof is easily carried out by injection molding.

For optical lenses, resins having various structures, which are to bereplaced for glass, have been developed, and various monomers have beenstudied as raw materials therefor. Among optical transparent resins, anoptical lens consisting of a thermoplastic transparent resin isadvantageous in that it can be produced in a large amount by injectionmolding, and further in that the production of an aspherical lens iseasy, and thus, it is presently used as a lens for cameras. As such anoptical transparent resin, for example, polycarbonate consisting ofbisphenol A (BPA) had been mainly used, but thereafter, polymers havinga fluorene skeleton such as 9,9-bis(4-(2-hydroxyethoxy)phenyl)fluorene(BPEF) (Patent Literatures 1 and 2) have been developed. Moreover, as amaterial having a high refractive index and low birefringence, a resincomprising, as a raw material monomer, a dihydroxy compound having abinaphthalene skeleton has been developed by the present inventors(Patent Literature 3).

Such a resin comprising, as a raw material monomer, a dihydroxy compoundhaving a binaphthalene skeleton is preferable as an optical material,but the resin is problematic in that it has a high saturated waterabsorption rate and a dimensional change easily occurs upon molding. Inaddition, if such a saturated water absorption rate is high, a longdrying time becomes necessary upon molding, and it may cause coloration.Accordingly, it has been desired to develop a resin that is useful as anoptical material and has a low saturated water absorption rate.

CITATION LIST Patent Literature

-   Patent Literature 1: International Publication WO2007/142149-   Patent Literature 2: International Publication WO2011/010741-   Patent Literature 3: International Publication WO2014/073496

SUMMARY OF INVENTION Technical Problem

It is an object of the present invention to provide a method forproducing a thermoplastic resin having a low saturated water absorptionrate.

Solution to Problem

As a result of intensive studies directed towards achieving theaforementioned object, the present inventors have found that theaforementioned object can be achieved by setting the content of aspecific dihydroxy compound in a dihydroxy compound having a specificbinaphthalene skeleton to be within a predetermined range, therebycompleting the present invention. Specifically, the present inventionis, for example, as follows.

[1] A method for producing a thermoplastic resin by reacting reactantscomprising a dihydroxy compound, wherein

the dihydroxy compound comprises a dihydroxy compound represented by thefollowing formula (1), wherein

the total weight of a compound represented by the following formula (A),a compound represented by the following formula (B), and a compoundrepresented by the following formula (C) in the dihydroxy compound is1,500 ppm or less, based on 100 parts by weight of the dihydroxycompound represented by the formula (1):

wherein X represents an alkylene group containing 1 to 4 carbon atoms,

[2] The production method according to the above [1], wherein thedihydroxy compound further comprises a compound represented by thefollowing formula (2):

wherein R₁ to R₄ are each independently selected from the groupconsisting of a hydrogen atom, an alkyl group containing 1 to 20 carbonatoms, an alkoxy group containing 1 to 20 carbon atoms, a cycloalkylgroup containing 5 to 20 carbon atoms, a cycloalkoxy group containing 5to 20 carbon atoms, an aryl group containing 6 to 20 carbon atoms, anaryloxy group containing 6 to 20 carbon atoms, and a halogen atom;

X each independently represents an alkylene group containing 2 to 8carbon atoms; and

n each independently represents an integer of 1 to 5.

[3] The production method according to the above [1] or [2], wherein theweight average molecular weight of the thermoplastic resin is 35,000 to70,000.

[4] The production method according to any one of the above [1] to [3],wherein the weight of the compound represented by the formula (A) in thedihydroxy compound is 300 ppm or less, based on 100 parts by weight ofthe dihydroxy compound represented by the formula (1).[5] The production method according to any one of the above [1] to [4],wherein the weight of the compound represented by the formula (B) in thedihydroxy compound is 100 ppm or less, based on 100 parts by weight ofthe dihydroxy compound represented by the formula (1).[6] The production method according to any one of the above [1] to [5],wherein the weight of the compound represented by the formula (C) in thedihydroxy compound is 100 ppm or less, based on 100 parts by weight ofthe dihydroxy compound represented by the formula (1).[7] The production method according to any one of the above [1] to [6],wherein the purity of the dihydroxy compound represented by the formula(1) is 99% or more.[8] The production method according to any one of the above [1] to [7],wherein the thermoplastic resin is selected from the group consisting ofa polycarbonate resin, a polyester resin, and a polyester carbonateresin.[9] The production method according to the above [8], wherein thethermoplastic resin is a polycarbonate resin.[10] The production method according to any one of the above [1] to [9],wherein the reactants further comprise carbonic acid diester.[11] The production method according to any one of the above [1] to[10], wherein the saturated water absorption rate of the thermoplasticresin is 0.39% by weight or less.[12] A method for producing an optical element, which is characterizedin that it uses a thermoplastic resin obtained by the production methodaccording to any one of the above [1] to [11].[13] A method for producing an optical lens, which is characterized inthat it uses a thermoplastic resin obtained by the production methodaccording to any one of the above [1] to [11].[141] A method for producing an optical film, which is characterized inthat it uses a thermoplastic resin obtained by the production methodaccording to any one of the above [1] to [11].

Effects of Invention

According to the present invention, a thermoplastic resin having a lowsaturated water absorption rate, in which a dimensional change hardlyoccurs upon molding, can be obtained.

DESCRIPTION OF EMBODIMENTS

Hereinafter, the present invention will be described in detail in thefollowing embodiments, illustrations and the like. However, the presentinvention is not limited to these embodiments, illustrations and thelike, and the present invention can be carried out by being arbitrarilymodified in a range in which such modification is not deviated from thegist of the present invention.

One embodiment of the present invention relates to a method forproducing a thermoplastic resin by reacting reactants comprising adihydroxy compound. In this production method, the dihydroxy compoundcomprises a dihydroxy compound represented by the following formula (1),wherein the total weight of a compound represented by the followingformula (A), a compound represented by the following formula (B), and acompound represented by the following formula (C) in the dihydroxycompound is 1,500 ppm or less, based on 100 parts by weight of thedihydroxy compound represented by the formula (1):

The dihydroxy compound represented by the formula (1) comprises aplurality of by-product compounds having a dinaphthol structure asimpurities generated in the process of synthesis. The present inventorshave found that, among such by-product compounds, the presence of thecompound represented by the formula (A), the compound represented by theformula (B) and/or the compound represented by the formula (C) causes anincrease in the saturated water absorption rate of a thermoplastic resinobtained by polymerizing the dihydroxy compound represented by theformula (1), and a reduction in the speed of the polymerizationreaction. Moreover, the present inventors have found that the speed ofthe polymerization reaction can be improved and the saturated waterabsorption rate of the thermoplastic resin obtained by thepolymerization can be reduced by using raw materials in which theaforementioned compounds are reduced.

One advantage provided by a low saturated water absorption rate is thata change in the dimension of a resin hardly takes place upon molding.Another advantage provided by a low saturated water absorption rate isthat drying can be carried out in a short time during molding and thecoloration of a resin can be thereby suppressed.

Moreover, according to the production method of the present invention,the speed of the polymerization reaction can also be improved. Anadvantage provided by the improvement of the polymerization reactionspeed is that a high-molecular-weight thermoplastic resin can beobtained in a short time. Thermoplastic resins having various molecularweights are demanded depending on various needs for optical materials.In general, if polymerization is carried out for a long period of timein order to obtain a high-molecular-weight resin, the coloration of aresin easily takes place. Thus, it is difficult to obtain ahigh-molecular-weight thermoplastic resin with a little coloration. Theproduction method of the present invention enables the production of ahigh-molecular-weight resin in a short time, and thus, it isadvantageous for the production of a thermoplastic resin as an opticalmaterial.

The production method of the present invention is characterized in thatthe total weight of the compound represented by the formula (A), thecompound represented by the formula (B), and the compound represented bythe formula (C), which are comprised in the dihydroxy compound as a rawmaterial for a thermoplastic resin, is 1.500 ppm or less, based on 100parts by weight of the dihydroxy compound represented by the formula(1). If the above-described total weight is 1500 ppm or less, the effectof reducing the saturated water absorption rate of the thermoplasticresin, and/or improving the polymerization reaction speed, can beobtained. The total weight of the compound represented by the formula(A), the compound represented by the formula (B), and the compoundrepresented by the formula (C) is preferably 1000 ppm or less, morepreferably 500 ppm or less, and further preferably 300 ppm or less. Thelower the lower limit value of the total weight of the compoundrepresented by the formula (A), the compound represented by the formula(B) and the compound represented by the formula (C), the more preferableit is. The lower limit value is, for example, 0 ppm, and it may also be1 ppm or more. The dihydroxy compound represented by the formula (1)generally comprises any of the compounds of the formulae (A), (B),and/or (C), which are generated as by-products in the synthetic processthereof. The technique of setting the total content of these compoundsto be less than 1 ppm imposes a great burden on purification techniques.Moreover, when the total content that is less than 1 ppm is comparedwith the total content that is 1 ppm, there is no significant differencein physical properties between the two cases.

In a preferred embodiment, the total weight of the compound representedby the formula (A) and the compound represented by the formula (B) inthe dihydroxy compound is 1000 ppm or less (more preferably, 500 ppm orless, and further preferably, 300 ppm or less), based on 100 parts byweight of the dihydroxy compound represented by the formula (1). Sincethe compound of the formula (A) and the compound of the formula (B) havean ethylene oxide chain and a phenolic hydroxyl group, these compoundshave high polarity and tend to improve hydrophilicity. Accordingly, byreducing the content of the compound of the formula (A) and the compoundof the formula (B), the saturated water absorption rate of the obtainthermoplastic resin can be further reduced.

From the viewpoint of a reduction in the saturated water absorption rateof the thermoplastic resin and the improvement of the polymerizationspeed, the weight of the compound represented by the formula (A) in thedihydroxy compound is preferably 300 ppm or less, and more preferably250 ppm or less, based on 100 parts by weight of the dihydroxy compoundrepresented by the formula (1). The lower limit is not particularlylimited, and it is for example, 0 ppm, or 1 ppm or more.

From the viewpoint of a reduction in the saturated water absorption rateof the thermoplastic resin and the improvement of the polymerizationspeed, the weight of the compound represented by the formula (B) in thedihydroxy compound is preferably 500 ppm or less, more preferably 300ppm or less, further preferably 100 ppm or less, particularly preferably50 ppm or less, and most preferably 25 ppm or less, based on 100 partsby weight of the dihydroxy compound represented by the formula (1). Thelower limit is not particularly limited, and it is for example, 0 ppm.

From the viewpoint of a reduction in the saturated water absorption rateof the thermoplastic resin and the improvement of the polymerizationspeed, the weight of the compound represented by the formula (C) in thedihydroxy compound is preferably 100 ppm or less, and more preferably 50ppm or less, based on 100 parts by weight of the dihydroxy compoundrepresented by the formula (1). The lower limit is not particularlylimited, and it is for example, 0 ppm.

The amounts of the compound represented by the formula (A), the compoundrepresented by the formula (B) and the compound represented by theformula (C) comprised in the dihydroxy compound can be measured by usinghigh performance liquid chromatography (HPLC). Measurement conditionsfor HPLC are, for example, are as follows.

(HPLC Measurement Conditions)

-   -   LC measurement device: LC-2010A, manufactured by Shimadzu        Corporation    -   Column: YMC-Pack ODS-AM (4.6 mm in diameter×250 mm, particle        diameter: 5 μm)    -   Column temperature: 25° C.    -   Mobile phase solvent: Pure water/acetonitrile (acetonitrile        20%→95%)    -   Flow rate: 1.0 mL/min    -   Detection method: UV (detection wavelength: 254 nm)    -   Sensitivity: 2.5 AU/V (AUXRNG6)    -   Sample: 50 mg/50 mL-acetonitrile

In the embodiment of the present invention, the purity of the dihydroxycompound represented by the formula (1) is 99% or more. In such a case,the compound represented by the formula (A), the compound represented bythe formula (B) and the compound represented by the formula (C) in thedihydroxy compound are reduced, and from the viewpoint of a reduction inthe saturated water absorption rate of the thermoplastic resin and theimprovement of the polymerization speed, it is preferable.

The method of reducing the compound represented by the formula (A), thecompound represented by the formula (B) and the compound represented bythe formula (C) in the dihydroxy compound is not particularly limited.Examples of the method include a method of purifying the dihydroxycompound represented by the formula (1) after the synthesis thereof(e.g., washing, filtration, etc.), and a method of changing conditionsfor synthesizing the dihydroxy compound represented by the formula (1)(e.g., the reaction temperature and the reaction time), the species ofthe reaction solvent, the amount of the solvent, etc.

The method for producing a thermoplastic resin according to oneembodiment comprises a step of purifying the dihydroxy compoundrepresented by the formula (1). The purification method is notparticularly limited, and examples of the purification method include afiltration treatment and/or a washing treatment using a washing solvent.The filtration treatment method is not particularly limited. The meshsize of a filter is preferably 7 μm or less, and more preferably 5 μm orless. The washing solvent is not particularly limited, and examples ofthe washing solvent include: aromatic hydrocarbon-based solvents such asbenzene, ethylbenzene, xylene, or ethyltoluene; aliphatic hydrocarbonssuch as pentane, hexane, or heptane; and water. Among these solvents,xylene and toluene are preferable. According to this method, the contentof at least one of the compound represented by the formula (A), thecompound represented by the formula (B), and the compound represented bythe formula (C), which are comprised in the dihydroxy compound, can besignificantly reduced.

The method for producing a thermoplastic resin according to oneembodiment further comprises a step of allowing 1,1′-bi-2-naphthol toreact with alkylene carbonate to obtain the dihydroxy compound of theformula (1), wherein the reaction is carried out at a temperature of110° C. or higher (preferably, 110° C. to 120° C., and more preferably110° C. to 115° C.). According to this method, the content of at leastone of the compound represented by the formula (A), the compoundrepresented by the formula (B), and the compound represented by theformula (C), which are comprised in the dihydroxy compound, can besignificantly reduced.

The reaction time is preferably 11 hours or shorter, more preferably 9to 11 hours, and further preferably 9 to 10 hours. The preferredreaction time can be fluctuated depending on the reaction scale.Besides, the reaction time means a time period required until an alkaliaqueous solution is added to a reactor, from a time point where thetemperature has reached a desired reaction temperature (e.g., 110° C.).

Hereafter, a thermoplastic resin obtained by the production method ofthe present invention will be described.

<Thermoplastic Resin>

A thermoplastic resin obtained by the production method according to theembodiment of the present invention is produced by reacting reactantscomprising the dihydroxy compound represented by the formula (1). Thisthermoplastic resin comprises a constituting unit (1)′ derived from thedihydroxy compound represented by the formula (1).

In the above formula (1)′, the symbol * represents a binding moiety.

A resin comprising the compound of the above formula (1) as a rawmaterial exhibits physical properties such as a high refractive index, alow Abbe number, high transparency, a glass transition temperaturesuitable for injection molding, and low birefringence. By using thisresin, optical components, such as excellent optical lens havingsubstantially no optical distortion can be obtained.

As a thermoplastic resin used herein, a polyester resin, a polyestercarbonate resin, or a polycarbonate resin is preferable. Among others,the thermoplastic resin preferably comprises a polycarbonate resin,since the polycarbonate resin is excellent in heat resistance andhydrolysis resistance. The thermoplastic resin may comprise theaforementioned resins, alone or in combination of two or more types.

Optical properties such as refractive index, Abbe number, andbirefringence value are greatly influenced by the chemical structure ofa constituting unit. On the other hand, whether the chemical bondbetween constituting units is an ester bond or a carbonate bond has arelatively small influence on such optical properties. Moreover, alsoregarding the influence of impurities (an increase in the saturatedwater absorption rate or a decrease in the polymerization speed), theinfluence of the chemical structure of a constituting unit thatconstitutes a resin is large, and the influence of a difference in thechemical bond (an ester bond or a carbonate bond) between constitutingunits is relatively small.

The thermoplastic resin according to the embodiment of the presentinvention is produced by reacting reactants comprising a dihydroxycompound. For example, the present thermoplastic resin is produced byperforming polycondensation using, as a raw material, a dihydroxycompound comprising the dihydroxy compound represented by the formula(1). In the compound represented by the formula (1), the functionalgroup contributing to polycondensation is an alcoholic hydroxyl group.By reacting the compound represented by the formula (1) with a carbonicacid diester and/or a dicarboxylic acid or a derivative thereofaccording to a polycondensation reaction, a constituting unit (1)′derived from the compound represented by the formula (1) is allowed tobind to a carbonic acid diester and/or a dicarboxylic acid or aderivative thereof via a carbonate bond and/or an ester bond. By usingthe dihydroxy compound represented by the formula (1) as a raw material,a thermoplastic resin comprising the constituting unit (1)′ derived fromthe dihydroxy compound represented by the formula (1) can be obtained.

In the formula (1), X each independently represents an alkylene groupcontaining 1 to 4 carbon atoms. Preferred examples of such an alkylenegroup containing 1 to 4 carbon atoms include a methylene group, anethylene group, a propylene group, an isopropylene group, an n-butylenegroup, an isobutylene group, a sec-butylene group, and a tert-butylenegroup. Among these groups, X is preferably always an ethylene groupbecause the melt fluidity of a resin becomes favorable upon molding.

Examples of the dihydroxy compound represented by the formula (1)include 2,2′-bis(1-hydroxymethoxy)-1,1′-binaphthalene,2,2′-bis(2-hydroxyethoxy)-1,1′-binaphthalene,2,2′-bis(3-hydroxypropyloxy)-1,1′-binaphthalene, and2,2′-bis(4-hydroxybutoxy)-1,1′-binaphthalene. Among these compounds,2,2′-bis(2-hydroxyethoxy)-1,1′-binaphthalene is preferable. Thesecompounds may be used alone, or may also be used in combination of twoor more types.

The percentage of the dihydroxy compound of the formula (1) ispreferably 1 to 100 mol %, more preferably 30 to 100 mol %, and furtherpreferably 40 to 100 mol %, based on 100 mol % of the dihydroxy compoundused as a raw material for a thermoplastic resin. Moreover, thepercentage of the dihydroxy compound of the formula (1) is preferably 1to 100 mol %, more preferably 30 to 100 mol %, and further preferably 40to 100 mol %, based on 100 mol % of all monomers used as raw materialsfor a thermoplastic resin.

As mentioned above, the above-described dihydroxy compound may compriseat least one of the compound represented by the formula (A), thecompound represented by the formula (B), and the compound represented bythe formula (C). In general, when the dihydroxy compound comprises thesecompounds, these compounds, together with the dihydroxy compound of theformula (1), are subjected to a polycondensation reaction, so that aconstituting unit (A)′ derived from the compound represented by theformula (A), a constituting unit (B)′ derived from the compoundrepresented by the formula (B), and/or a constituting unit (C)′ derivedfrom the compound represented by the formula (C) can be incorporatedinto the thermoplastic resin.

In the above formula (A)′, (B)′, or (C)′, the symbol * represents abinding moiety.

(Other Dihydroxy Components)

In the present invention, as dihydroxy components, other dihydroxycompounds can be used in combination with the compound represented bythe formula (1). For example, the dihydroxy compound further comprisesthe dihydroxy compound represented by the formula (2), as well as thedihydroxy compound represented by the formula (1). Using such adihydroxy compound as a raw material, the obtained thermoplastic resinfurther comprises a constituting unit (2)′ derived from the dihydroxycompound represented by the formula (2), as well as the constitutingunit (1)′ derived from the dihydroxy compound represented by the formula(1).

In the above formula (2)′, the symbol * represents a binding moiety.

In the compound represented by the formula (2), the functional groupcontributing to polycondensation is an alcoholic hydroxyl group or aphenolic hydroxyl group. By using the dihydroxy compound of the formula(2) as a raw material, the obtained thermoplastic resin has theconstituting unit (2)′ derived from the compound represented by theformula (2). The constituting unit (2)′ derived from the compoundrepresented by the formula (2) contributes to a high refractive index.By allowing the thermoplastic resin to comprise the constituting unit(1)′ and the constituting unit (2)′, the effect of reducing thebirefringence value of the entire resin and reducing the opticaldistortion of an optical molded body can be obtained.

In the formula (2), R₁ to R₄ each independently represent a hydrogenatom, an alkyl group containing 1 to 20 carbon atoms, an alkoxy groupcontaining 1 to 20 carbon atoms, a cycloalkyl group containing 5 to 20carbon atoms, a cycloalkoxy group containing 5 to 20 carbon atoms, anaryl group containing 6 to 20 carbon atoms, an aryloxy group containing6 to 20 carbon atoms, or a halogen atom (F, Cl, Br, or I). Among others,a compound in which R¹ to R⁴ are hydrogen atoms is preferable, since themelt fluidity becomes favorable when it is molded into an optical lens.In addition, a compound, in which R¹ and R² are hydrogen atoms and R³and R⁴ are aryl groups each containing 6 to 20 carbon atoms (preferably,phenyl groups), is preferable, since the optical properties of thethermoplastic resin become favorable.

In the formula (2), X each independently represents an alkylene groupcontaining 2 to 8 carbon atoms. As the number of carbon atoms containedin X increases, melt viscosity decreases, and toughness and moldabilityare improved. Accordingly, a compound having an alkylene groupcontaining 2 or more carbon atoms is preferable. On the other hand, asthe number of carbon atoms contained in X increases, the glasstransition temperature decreases. Accordingly, from the viewpoint ofheat resistance, an alkylene group containing 3 or less carbon atoms ispreferable. From the viewpoint of achieving both excellent moldingeasiness and heat resistance, the number of carbon atoms contained ismore preferably 2 or 3, and in particular, from the viewpoint of beingexcellent in the refractive index and the production and distribution ofmonomers, X is preferably an ethylene group containing 2 carbon atoms.

In the formula (2), n each independently represents an integer of 1 to5. Among others, in terms of excellent heat stability and easyavailability, n is preferably 1.

Examples of the compound represented by the formula (2) include9,9-bis(4-(2-hydroxyethoxy)phenyl)fluorene,9,9-bis(4-(2-hydroxyethoxy)-3-methylphenyl)fluorene,9,9-bis(4-(2-hydroxyethoxy)-3,5-dimethylphenyl)fluorene,9,9-bis(4-(2-hydroxyethoxy)-3-tert-butylphenyl)fluorene,9,9-bis(4-(2-hydroxyethoxy)-3-isopropylphenyl)fluorene,9,9-bis(4-(2-hydroxyethoxy)-3-cyclohexylphenyl)fluorene, and9,9-bis(4-(2-hydroxyethoxy)-3-phenylphenyl)fluorene. Among thesecompounds, 9,9-bis(4-(2-hydroxyethoxy)-3-phenylphenyl)fluorene and9,9-bis(4-(2-hydroxyethoxy)phenyl)fluorene are preferable, and9,9-bis(4-(2-hydroxyethoxy)phenyl)fluorene is more preferable. Thesecompounds may be used alone, or may also be used in combination of twoor more types.

The total amount of the dihydroxy compound of the formula (1) and thedihydroxy compound of the formula (2) is preferably 50 mol % or more,more preferably 80 mol % or more, particularly preferably 90 mol % ormore, and most preferably 100 mol %, based on 100 mol % of the dihydroxycompound used as a raw material for a thermoplastic resin. The molarratio between the dihydroxy compound of the formula (1) and thedihydroxy compound of the formula (2) (the constituting unit (1)′ andthe constituting unit (2)′) is preferably 20/80 to 80/20, morepreferably 30/70 to 80/20, and from the viewpoint of a reduction in thesaturated water absorption rate, the aforementioned molar ratio isfurther preferably 30/70 to 50/50, and particularly preferably 40/60 to50/50.

The dihydroxy compound may comprise constituting units derived fromdihydroxy compounds other than the above-described compounds of theformulae (1) and (2). Examples of such other dihydroxy compoundsinclude: alicyclic dihydroxy compounds such astricyclodecane[5.2.1.0^(2,6)]dimethanol, pentacyclopentadecanedimethanol, cyclohexane-1,2-dimethanol, cyclohexane-1,4-dimethanol,cyclohexane-1,3-dimethanol, decaline-2,6-dimethanol,decaline-2,3-dimethanol, decaline-1,5-dimethanol, 2,3-norbornanedimethanol, 2,5-norbornane dimethanol, or 1,3-adamantane dimethanol;aliphatic dihydroxy compounds such as ethylene glycol, 1,3-propanediol,1,2-propanediol, 1,4-butanediol, 1,3-butanediol, 1,2-butanediol,1,5-pentanediol, 1,6-hexanediol, 1,5-heptanediol, 1,8-octanediol,1,9-nonanediol, 1,10-decanediol, or spiroglycol; and aromatic dihydroxycompounds such as 4,4-bis(4-hydroxyphenyl)propane (i.e., bisphenol A),1,1-bis(4-hydroxyphenyl)-1-phenylethane (i.e., bisphenol AP),2,2-bis(4-hydroxyphenyl)hexafluoropropane (i.e., bisphenol AF),2,2-bis(4-hydroxyphenyl)butane (i.e., bisphenol B),bis(4-hydroxyphenyl)diphenylmethane (i.e., bisphenol BP),bis(4-hydroxy-3-methylphenyl)propane (i.e., bisphenol C),2,2-bis(4-hydroxy-3,5-dimethylphenyl)propane,2,2-bis(4-hydroxy-3,5-diethylphenyl)propane,2,2-bis(4-hydroxy-(3,5-diphenyl)phenyl)propane,2,2-bis(4-hydroxy-3,5-dibromophenyl)propane,1,1-bis(4-hydroxyphenyl)ethane (i.e., bisphenol E),bis(4-hydroxyphenyl)methane (i.e., bisphenol F),2,4′-dihydroxy-diphenylmethane, bis(2-hydroxyphenyl)methane,2,2-bis(4-hydroxy-3-isopropylphenyl)propane (i.e., bisphenol G),1,3-bis(2-(4-hydroxyphenyl)-2-propyl)benzene (i.e., bisphenol M),bis(4-hydroxyphenyl)sulfone (i.e., bisphenol S),2,4′-dihydroxydiphenylsulfone, bis(4-hydroxyphenyl)sulfide,1,4-bis(2-(4-hydroxyphenyl)-2-propyl)benzene (i.e., bisphenol P),bis(4-hydroxy-3-phenylphenyl]propane (i.e., bisphenol PH),1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane (i.e., bisphenolTMC), 1,1-bis(4-hydroxyphenyl)cyclohexane (i.e., bisphenol Z),1,1-bis(4-hydroxy-3-methylphenyl)cyclohexane (i.e., bisphenol OCZ),3,3-bis(4-hydroxyphenyl)pentane, 4,4-biphenol,9,9-bis(4-(2-hydroxyethoxy)phenyl)fluorene,9,9-bis(4-hydroxy-2-methylphenyl)fluorene,9,9-bis(4-hydroxyphenyl)fluorene,9,9-bis(4-(2-hydroxyethoxy)-3-methylphenyl)fluorene,9,9-bis(4-(2-hydroxyethoxy)-3-tert-butylphenyl)fluorene,9,9-bis(4-(2-hydroxyethoxy)-3-isopropylphenyl)fluorene,9,9-bis(4-(2-hydroxyethoxy)-3-cyclohexylphenyl)fluorene,9,9-bis(4-(2-hydroxyethoxy)-3-phenylphenyl)fluorene,2.2-bis(4-hydroxyphenyl)pentane, 4,4′-dihydroxydiphenyl ether, or4,4′-dihydroxy-3,3′-dichlorodiphenyl ether.

Other dihydroxy compounds are added in an amount of desirably 20 mol %or less, and more desirably 10 mol % or less, based on 100 mol % of thecompound of the formula (1). If the amount of other hydroxyl compoundsis in this range, a high refractive index can be retained.

In order to maintain optical distortion at a low level, thethermoplastic resin is preferably a resin consisting of the constitutingunit (1)′ derived from the dihydroxy compound of the formula (1) (firstaspect), or a resin consisting of the constituting unit (1)′ derivedfrom the dihydroxy compound of the formula (1) and the constituting unit(2)′ derived from the dihydroxy compound of the formula (2) (secondaspect). The thermoplastic resins of the first aspect and the secondaspect (polycarbonate resin, polyester resin, and polyester carbonateresin) may be used by being mixed with one another, or can also be usedby being mixed with other resins. The phrase “a resin consisting of theconstituting unit (1)′ and/or the constituting unit (2)′” means that therepeating units in the resin, other than a carbonate bond moiety and anester bond moiety, consist of the constituting unit (1)′ and theconstituting unit (2)′. Besides, the polycarbonate bond moiety isderived from a carbonate precursor substance such as phosgene orcarbonic acid diester.

The weight average molecular weight of the thermoplastic resin ispreferably 10,000 to 100,000. The weight average molecular weight (Mw)of the thermoplastic resin means a weight average molecular weight interms of styrene, and it is measured by the method described in theafter-mentioned Examples. If Mw is 10,000 or more, the brittlenessreduction of the molded body is prevented. If Mw is 100,000 or less,melt viscosity does not become too high, and thus, it is easy to removethe resin from a metallic mold upon molding. Moreover, good fluidity isachieved, and it is preferable for the injection molding of opticallenses and the like in a melted state, which is required to haveprecision. From the viewpoint of preventing the coloration of the resinand maintaining the strength of a molded body, the weight averagemolecular weight (Mw) is more preferably 35,000 to 70,000, and furtherpreferably 40,000 to 65,000.

When the thermoplastic resin is used in injection molding, the glasstransition temperature (Tg) is preferably 95° C. to 180° C., morepreferably 110° C. to 170° C., further preferably 115° C. to 160° C.,particularly preferably 125° C. to 145° C. If Tg is lower than 95° C.,the range of the used temperature is unfavorably narrowed. On the otherhand, if Tg exceeds 180° C. the melting temperature of the resin becomeshigh, and the decomposition or coloration of the resin is unfavorablyeasily generated. Moreover, when the glass transition temperature of theresin is too high, a different between the metallic mold temperature andthe glass transition temperature of the resin becomes large, if acommonly used metallic mold temperature controller is used. Hence, inthe intended use for which products are required to have high profileirregularity, it is difficult and thus unfavorable to use a resin havingan extremely high glass transition temperature.

As an indicator of heat stability for enduring heating upon theinjection molding of the thermoplastic resin, the 5% weight losstemperature (Td), which is measured at a temperature-increasing rate of10° C./min, is preferably 350° C. or higher. When the 5% weight losstemperature is lower than 350° C., thermal decomposition significantlytakes place upon molding, and thus, it unfavorably becomes difficult toobtain a good molded body.

The thermoplastic resin may have any structure of random, block, andalternating copolymers.

In the thermoplastic resin, phenol generated upon the production thereofor unreacted remaining carbonic acid diester is present as an impurity.The content of such phenol in the thermoplastic resin is preferably 0.1to 3000 ppm, more preferably 0.1 to 2000 ppm, and particularlypreferably 1 to 1000 ppm, 1 to 800 ppm, 1 to 500 ppm, or 1 to 300 ppm.In addition, the content of such carbonic acid diester in apolycarbonate resin or a polyester carbonate resin is preferably 0.1 to1000 ppm, more preferably 0.1 to 500 ppm, and particularly preferably 1to 100 ppm. By controlling the amounts of phenol and carbonic aciddiester contained in the resin, a resin having physical propertiesdepending on purpose can be obtained. The contents of phenol andcarbonic acid diester can be controlled, as appropriate, by changingconditions or devices for polycondensation. Moreover, such contents canalso be controlled by changing conditions applied in an extrusion stepfollowing polycondensation.

If the content of phenol or carbonic acid diester is higher than theabove-described range, problems may occur, such as a reduction in thestrength of the obtained resin molded body or generation of odor. Incontrast, if the content of phenol or carbonic acid diester is lowerthan the above-described range, it may be likely that plasticity isreduced upon the melting of the resin.

The thermoplastic resin according to the embodiment desirably comprisesforeign matters in extremely small amounts, and thus, it is preferableto carry out filtration of melted raw materials, filtration of acatalyst solution, and filtration of melted oligomers. The mesh size ofa filter is preferably 7 μm or less, and more preferably 5 μm or less.Moreover, it is also preferable to filtrate the generated resin througha polymer filter. The mesh size of a polymer filter is preferably 100 μmor less, and more preferably 30 μm or less. Furthermore, a step ofcollecting resin pellets must be naturally carried out under a low-dustenvironment, and the class is preferably 6 or less, and more preferably5 or less.

To the thermoplastic resin of the present invention, an antioxidant, arelease agent, an ultraviolet absorber, a fluidity modifier, a crystalnucleating agent, a reinforcer, a dye, an antistatic agent, anantibacterial agent, and the like may be added.

Hereafter, a polycarbonate resin will be exemplified and explained asone example of thermoplastic resins. A polyester resin and a polyestercarbonate resin can also be carried out with reference to thedescription of the following (Polycarbonate resin), and/or by applying apublicly known method.

(Polycarbonate Resin)

The polycarbonate resin according to the embodiment is a polycarbonateresin comprising the constituting unit (1)′ derived from the compoundrepresented by the above formula (1), and as necessary, theaforementioned other constituting units. The polycarbonate resin isgenerated by allowing a dihydroxy compound to react with a carbonateprecursor substance such as carbonic acid diester, and individualconstituting units bind to one another via a carbonate bond. In oneembodiment, reactants further comprise carbonic acid diester, as well asa dihydroxy compound.

Specifically, the polycarbonate resin according to the embodiment can beproduced by allowing a dihydroxy compound comprising the compoundrepresented by the above formula (1) to react with a carbonate precursorsubstance such as carbonic acid diester according to a meltpolycondensation method, in the presence of a transesterificationcatalyst or in the absence of a catalyst.

Examples of the carbonic acid diester include diphenyl carbonate,ditolyl carbonate, bis(chlorophenyl) carbonate, m-cresyl carbonate,dimethyl carbonate, diethyl carbonate, dibutyl carbonate, anddicyclohexyl carbonate. Among these compounds, diphenyl carbonate isparticularly preferable. The diphenyl carbonate is used at a ratio ofpreferably 0.97 to 1.20 moles, and more preferably 0.98 to 1.10 moles,based on total 1 mole of the dihydroxy compound.

An example of the production method is a method comprising stirringdihydroxy compound components and carbonic acid diester to melt themunder an inert gas atmosphere, while heating, and then polymerizingthem, while distilling away the generated alcohols or phenols. Thereaction temperature is different depending on the boiling point of thegenerated alcohols or phenols, etc., but it is generally in the rangefrom 120° C. to 350° C. From the initial stage of the reaction, thepressure is reduced, and the reaction is then terminated whiledistilling away the generated alcohols or phenols. Moreover, in order topromote the reaction, a transesterification catalyst can also be used.

With regard to melt polycondensation in the present composition system,a dihydroxy compound comprising the compound represented by the formula(1) and carbonic acid diester are melted in a reactor, and thereafter,while monohydroxy compounds generated as by-products are distilled away,the reaction is carried out. The reaction time is 200 minutes or longerand 500 minutes or shorter, preferably 250 minutes or longer and 450minutes or shorter, and particularly preferably 300 minutes or longerand 40 minutes or shorter. The preferred reaction time can be fluctuateddepending on the reaction scale. Besides, the reaction time means a timeperiod required until nitrogen is introduced into the reactor, from atime point where raw materials have been dissolved (i.e., a time pointwhere stirring has become possible) (for example, after the temperaturehas reached 180° C.)).

The reaction may be carried out in a continuous system or in a batchsystem. The reactor used upon performing the reaction may be a verticalreactor equipped with an anchor impeller, a MAXBLEND impeller, a helicalribbon impeller, etc., or a horizontal reactor equipped with a paddleblade, a lattice blade, a spectacle blade etc., or an extruder-typereactor equipped with a screw. Furthermore, taking into considerationthe viscosity of a polymer, a reactor, in which the aforementionedreactors are appropriately combined with one another, can preferably beused.

As such a transesterification catalyst, a basic compound catalyst isused. Examples of such a basic compound catalyst include an alkalinemetal compound, an alkaline-earth metal compound, and anitrogen-containing compound.

Examples of the alkaline metal compound include the organic acid salt,inorganic acid salt, oxide, hydroxide, hydride, or alkoxide of alkalinemetals. Specific examples of the alkaline metal compound used hereininclude sodium hydroxide, potassium hydroxide, cesium hydroxide, lithiumhydroxide, sodium hydrogen carbonate, sodium carbonate, potassiumcarbonate, cesium carbonate, lithium carbonate, sodium acetate,potassium acetate, cesium acetate, lithium acetate, sodium stearate,potassium stearate, cesium stearate, lithium stearate, sodiumborohydride, sodium borophenylate, sodium benzoate, potassium benzoate,cesium benzoate, lithium benzoate, disodium hydrogen phosphate,dipotassium hydrogen phosphate, dilithium hydrogen phosphate, disodiumphenyl phosphate, the disodium salt, dipotassium salt, dicesium salt ordilithium salt of bisphenol A, and the sodium salt, potassium salt,cesium salt or lithium salt of phenol.

Examples of the alkaline-earth metal compound include the organic acidsalt, inorganic acid salt, oxide, hydroxide, hydride, or alkoxide of analkaline-earth metal compound. Specific examples of the alkaline-earthmetal compound used herein include magnesium hydroxide, calciumhydroxide, strontium hydroxide, barium hydroxide, magnesium hydrogencarbonate, calcium hydrogen carbonate, strontium hydrogen carbonate,barium hydrogen carbonate, magnesium carbonate, calcium carbonate,strontium carbonate, barium carbonate, magnesium acetate, calciumacetate, strontium acetate, barium acetate, magnesium stearate, calciumstearate, calcium benzoate, and magnesium phenyl phosphate.

Examples of the nitrogen-containing compound include quaternary ammoniumhydroxide and a salt thereof, and amines. Specific examples of thenitrogen-containing compound used herein include: quaternary ammoniumhydroxides having an alkyl group, an aryl group, etc., such astetramethylammonium hydroxide, tetraethylammonium hydroxide,tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, ortrimethylbenzylammonium hydroxide; tertiary amines, such astriethylamine, dimethylbenzylamine, or triphenylamine; secondary amines,such as diethylamine or dibutylamine; primary amines, such aspropylamine or butylamine; imidazoles, such as 2-methylimidazole,2-phenylimidazole, or benzimidazole; and bases or basic salts, such asammonia, tetramethylammonium borohydride, tetrabutylammoniumborohydride, tetrabutylammonium tetraphenylborate, ortetraphenylammonium tetraphenylborate.

As other transesterification catalysts, the salts of zinc, tin,zirconium, lead, etc. may also be used. These salts can be used alone orin combination. Specific examples of other transesterification catalystsinclude zinc acetate, zinc benzoate, zinc 2-ethylhexanoate, tin(II)chloride, tin(IV) chloride, tin(II) acetate, tin(IV) acetate, dibutyltinlaurate, dibutyltin oxide, dibutyltin dimethoxide, zirconiumacetylacetonate, zirconium oxyacetate, zirconium tetrabutoxide, lead(II)acetate, and lead(IV) acetate.

The transesterification catalyst is used at a ratio of 1×10⁻⁹ to ×10⁻³moles, and preferably 1×10⁻⁷ to 1×10⁻⁴ moles, based on total 1 mole ofthe dihydroxy compound.

The catalysts may be used in combination of two or more types. Inaddition, the catalyst itself may be directly added to the reactants, ormay be dissolved in a solvent such as water or phenol and may be thenadded to the reactants.

In the melt polycondensation method, melt polycondensation is carriedout using the above-described raw materials and catalysts, underheating, and further, under an ordinary or reduced pressure, whileby-products are removed by a transesterification reaction. The catalystmay be added together with raw materials at the initial stage of thereaction, or may be added in the course of the reaction.

In the method for producing a thermoplastic resin of the presentinvention, in order to retain heat stability and hydrolytic stability,the catalyst may be removed or deactivated after completion of thepolymerization reaction. However, the catalyst is not necessarilydeactivated. In the case of deactivating the catalyst a method fordeactivating a catalyst by addition of a known acidic substance can bepreferably carried out. Specific examples of such an acidic substance,which can be preferably used herein, include: esters such as butylbenzoate; aromatic sulfonic acids such as p-toluenesulfonic acid;aromatic sulfonic acid esters such as butyl p-toluenesulfonate or hexylp-toluenesulfonate; phosphoric acids such as phosphorous acid,phosphoric acid, or phosphonic acid; phosphorous acid esters such astriphenyl phosphite, monophenyl phosphite, diphenyl phosphite, diethylphosphite, di-n-propyl phosphite, di-n-butyl phosphite, di-n-hexylphosphite, dioctyl phosphite, or monooctyl phosphite; phosphoric acidesters such as triphenyl phosphate, diphenyl phosphate, monophenylphosphate, dibutyl phosphate, dioctyl phosphate, or monooctyl phosphate;phosphonic acids such as diphenyl phosphonate, dioctyl phosphonate, ordibutyl phosphonate; phosphonic acid esters such as diethylphenylphosphonate; phosphines such as triphenylphosphine orbis(diphenylphosphino)ethane; boric acids such as boric acid orphenylbonic acid; aromatic sulfonates such as tetrabutylphosphoniumdodecylbenzenesulfonate; organic halides such as stearoyl chloride,benzoyl chloride, or p-toluenesulfonyl chloride; alkyl sulfates such asdimethyl sulfate; and organic halides such as benzyl chloride. From theviewpoint of the effects of the deactivator, the stability to the resin,etc., p-toluene or butyl sulfonate is particularly preferable. Thedeactivator is used in a molar amount that is 0.01 to 50 times, andpreferably 0.3 to 20 times higher than the amount of the catalyst. Ifthe molar amount of the deactivator is smaller than 0.01 time the molaramount of the catalyst, deactivation effects unfavorably becomeinsufficient. On the other hand, if the molar amount of the deactivatoris larger than 50 times the molar amount of the catalyst, the heatresistance of the resin is reduced, and the obtained molded body isunfavorably easily colored.

The deactivator may be kneaded immediately after completion of thepolymerization reaction. Otherwise, the deactivator may also be kneaded,after the resin has been pelletized after completion of thepolymerization. Moreover, in addition to the deactivator, otheradditives (e.g., the after-mentioned antioxidant, release agent,ultraviolet absorber, fluidity modifier, crystal nucleating agent,reinforcer, dye, antistatic agent, antibacterial agent, etc.) can alsobe added by the same method as described above.

After deactivation of the catalyst (or, after completion of thepolymerization reaction, if the activator is not added), it may beappropriate to establish a step of devolatizing and removinglow-boiling-point compounds from the polymer under a pressure of 0.1 to1 mmHg and at a temperature of 200° C. to 350° C. The temperatureapplied upon such devolatilization and removal is preferably 230° C. to300° C., and more preferably 250° C. to 270° C. In this step, ahorizontal device equipped with an impeller having excellent surfacerenewal capacity, such as a paddle blade, a lattice blade or a spectacleblade, or a thin-film evaporator is preferably used.

(Other Additive Components)

To the thermoplastic resin, additives such as an antioxidant, aprocessing stabilizer, a light stabilizer, a polymerization metalinactivating agent, a fire retardant, a lubricant, an antistatic agent,a surfactant, an antibacterial agent, a release agent, an ultravioletabsorber, a plasticizer, and a compatibilizer may be added, in the rangein which they do not impair the characteristics of the presentinvention.

Examples of the antioxidant include triethyleneglycol-bis[3-(3-tert-butyl-5-methyl-4-hydroxyphenyl)propionate],1,6-hexanediol-bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate],pentaerythritol-tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate],octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate,1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene,N,N-hexamethylenebis(3,5-di-tert-butyl-4-hydroxy-hydrocinnamide),3,5-di-tert-butyl-4-hydroxy-benzylphosphonate-diethyl ester,tris(3,5-di-tert-butyl-4-hydroxybenzyl)isocyanurate, and 3,9-bis{1,1-dimethyl-2-[β-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionyloxy]ethyl}-2,4,8,10-tetraoxaspiro(5,5)undecane.The content of the antioxidant is preferably 0.001 to 0.3 parts byweight based on 100 parts by weight of the thermoplastic resin.

Examples of the processing stabilizer include a phosphorus-basedprocessing heat stabilizer and a sulfur-based processing heatstabilizer. Examples of the phosphorus-based processing heat stabilizerinclude phosphorous acid, phosphoric acid, phosphonous acid, phosphonicacid, and esters thereof. Specific examples include triphenyl phosphite,tris(nonylphenyl) phosphite, tris(2,4-di-tert-butylphenyl) phosphite,tris(2,6-di-tert-butylphenyl) phosphite, tridecyl phosphite, trioctylphosphite, trioctadecyl phosphite, didecylmonophenyl phosphite,dioctylmonophenyl phosphite, diisopropylmonophenyl phosphite,monobutyldiphenyl phosphite, monodecyldiphenyl phosphite,monooctyldiphenyl phosphite,bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite,2,2-methylenebis(4,6-di-tert-butylphenyl)octyl phosphite,bis(nonylphenyl)pentaerythritol diphosphite,bis(2,4-dicumylphenyl)pentaerythritol diphosphite,bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite,distearylpentaerythritol diphosphite, tributyl phosphate, triethylphosphate, trimethyl phosphate, triphenyl phosphate,diphenylmonoorthoxenyl phosphate, dibutyl phosphate, dioctyl phosphate,diisopropyl phosphate, dimethyl benzenephosphonate, diethylbenzenephosphonate, dipropyl benzenephosphonate,tetrakis(2,4-di-tert-butylphenyl)-4,4′-biphenylene diphosphonite,tetrakis(2,4-di-tert-butylphenyl)-4,3′-biphenylene diphosphonite,tetrakis(2,4-di-tert-butylphenyl)-3,3′-biphenylene diphosphonite,bis(2,4-di-tert-butylphenyl)-4-phenyl-phenyl phosphonite, andbis(2,4-di-tert-butylphenyl)-3-phenyl-phenyl phosphonite. The content ofthe phosphorus-based processing heat stabilizer is preferably 0.001 to0.2 parts by weight based on 100 parts by weight of the thermoplasticresin.

Examples of the sulfur-based processing heat stabilizer includepentaerythritol-tetrakis(3-laurylthiopropionate),pentaerythritol-tetrakis(3-mristylthiopropionate),pentaerythritol-tetrakis(3-stearylthiopropionate),dilaurl-3,3′-thiodipropionate, dimyristyl-3,3′-thiodipropionate, anddistearyl-3,3′-thiodipropionate. The content of the sulfur-basedprocessing heat stabilizer is preferably 0.001 to 0.2 parts by weightbased on 100 parts by weight of the thermoplastic resin.

A preferred release agent is a release agent, 90% by weight or more ofwhich consists of esters of alcohol and fatty acid. Specific examples ofsuch esters of alcohol and fatty acid include esters of monohydricalcohol and fatty acid, and partial esters or total esters of polyhydricalcohol and fatty acid. The above-described esters of monohydric alcoholand fatty acid are preferably esters of monohydric alcohol containing 1to 20 carbon atoms and saturated fatty acid containing 10 to 30 carbonatoms. Moreover, the above-described partial esters or total esters ofpolyhydric alcohol and fatty acid are preferably partial esters or totalesters of polyhydric alcohol containing 1 to 25 carbon atoms andsaturated fatty acid containing 10 to 30 carbon atoms.

Specific examples of the esters of monohydric alcohol and saturatedfatty acid include stearyl stearate, palmityl palmitate, butyl stearate,methyl laurate, and isopropyl palmitate. Specific examples of thepartial esters or total esters of polyhydric alcohol and saturated fattyacid include total esters or partial esters of dipentaerythritol, suchas monoglyceride stearate, diglyceride stearate, triglyceride stearate,monosorbitate stearate, monoglyceride behenate, monoglyceride caprate,monoglyceride laurate, pentaerythritol monostearate, pentaerythritoltetrastearate, pentaerythritol tetrapelargonate, propylene glycolmonostearate, biphenyl biphenate, sorbitan monostearate, 2-ethylhexylstearate, or dipentaerythritol hexastearate. Among these compounds,monoglyceride stearate and monoglyceride laurate are particularlypreferable. The content of such a release agent is preferably in therange of 0.005 to 2.0 parts by weight, more preferably in the range of0.01 to 0.6 parts by weight, and further preferably in the range of 0.02to 0.5 parts by weight, based on 100 parts by weight of thethermoplastic resin.

A preferred ultraviolet absorber is at least one ultraviolet absorberselected from the group consisting of a benzotriazole-based ultravioletabsorber, a benzophenone-based ultraviolet absorber, a triazine-basedultraviolet absorber, a cyclic imino ester-based ultraviolet absorberand a cyanoacrylate-based ultraviolet absorber. That is to say, thefollowing ultraviolet absorbers may be used alone or in combination oftwo or more types.

Examples of the benzotriazole-based ultraviolet absorber include2-(2-hydroxy-5-methylphenyl)benzotriazole,2-(2-hydroxy-5-tert-octylphenyl)benzotriazole,2-(2-hydroxy-3,5-dicumylphenyl)phenylbenzotriazole,2-(2-hydroxy-3-tert-butyl-5-methylphenyl)-5-chlorobenzotriazole,2,2′-methylenebis[4-(1,1,3,3-tetramethylbutyl)-6-(2N-benzotriazol-2-yl)phenol],2-(2-hydroxy-3,5-di-tert-butylphenyl)benzotriazole,2-(2-hydroxy-3,5-di-tert-butylphenyl)-5-chlorobenzotriazole,2-(2-hydroxy-3,5-di-tert-amylphenyl)benzotriazole,2-(2-hydroxy-5-tert-octylphenyl)benzotriazole,2-(2-hydroxy-5-tert-butylphenyl)benzotriazole,2-(2-hydroxy-4-octoxyphenyl)benzotriazole,2,2′-methylenebis(4-cumyl-6-benzotriazolephenyl),2,2′-p-phenylenebis(1,3-benzoxazin-4-one), and2-[2-hydroxy-3-(3,4,5,6-tetrahydrophthalimidemethyl)-5-methylphenyl]benzotriazole.

Examples of the benzophenone-based ultraviolet absorber include2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone,2-hydroxy-4-octoxybenzophenone, 2-hydroxy-4-benzyloxybenzophenone,2-hydroxy-4-methoxy-5-sulfoxybenzophenone,2-hydroxy-4-methoxy-5-sulfoxytrihydridatebenzophenone,2,2′-dihydroxy-4-methoxybenzophenone,2,2′,4,4′-tetrahydroxybenzophenone,2,2′-dihydroxy-4,4′-dimethoxybenzophenone,2,2′-dihydroxy-4,4′-dimethoxy-5-sodium sulfoxybenzophenone,bis(5-benzoyl-4-hydroxy-2-methoxyphenyl)methane,2-hydroxy-4-n-dodecyloxybenzophenone, and2-hydroxy-4-methoxy-2′-carboxybenzophenone.

Examples of the triazine-based ultraviolet absorber include2-(4,6-diphenyl-1,3,5-triazin-2-yl)-5-[(hexyl)oxy]-phenol and2-(4,6-bis(2,4-dimethylphenyl)-1,3,5-triazin-2-yl)-5-[(octyl)oxy]-phenol.

Examples of the cyclic imino ester-based ultraviolet absorber include2,2′-bis(3,1-benzoxazin-4-one),2,2′-p-phenylenebis(3,1-benzoxazin-4-one),2,2′-m-phenylenebis(3,1-benzoxazin-4-one),2,2′-(4,4′-diphenylene)bis(3,1-benzoxazin-4-one),2,2′-(2,6-naphthalene)bis(3,1-benzoxazin-4-one),2,2′-(1,5-naphthalene)bis(3,1-benzoxazin-4-one),2,2′-(2-methyl-p-phenylene)bis(3,1-benzoxazin-4-one),2,2′-(2-nitro-p-phenylene)bis(3,1-benzoxazin-4-one), and2,2′-(2-chloro-p-phenylene)bis(3,1-benzoxazin-4-one).

Examples of the cyanoacrylate-based ultraviolet absorber include1,3-bis-[(2′-cyano-3′,3′-diphenylacryloyl)oxy]-2,2-bis[(2-cyano-3,3-diphenylacryloyl)oxy]methyl)propaneand 1,3-bis-[(2-cyano-3,3-diphenylacryloyl)oxy]benzene.

The content of the ultraviolet absorber is preferably 0.01 to 3.0 partsby weight, more preferably 0.02 to 1.0 parts by weight, and furtherpreferably 0.05 to 0.8 parts by weight, based on 100 parts by weight ofthe thermoplastic resin. If the ultraviolet absorber is used in such amixed amount, it is possible to impart sufficient weather resistance tothe thermoplastic resin, depending on intended use.

In addition to the aforementioned thermoplastic resin, other resins mayalso be used in combination, in the range in which they do not impairthe characteristics of the present invention. That is to say, thethermoplastic resin of the present invention may be provided in the formof a resin composition comprising multiple types of resins. The resincomposition comprises at least a thermoplastic resin containing 1% to100% by weight of the repeating unit represented by the above formula(1).

Examples of other resins are as follows:

polyethylene, polypropylene, polyvinyl chloride, polystyrene, a(meth)acrylic resin, an ABS resin, polyamide, polyacetal, polycarbonate(provided that it does not comprise the constituting unit (1)′),polyphenylene ether, polyester (provided that it does not comprise theconstituting unit (1)′), polyester carbonate (provided that it does notcomprise the constituting unit (1)′), polyphenylene sulfide, polyimide,polyether sulfone, polyether ether ketone, a fluorine resin, acycloolefin polymer, an ethylene-vinyl acetate copolymer, an epoxyresin, a silicone resin, a phenolic resin, an unsaturated polyesterresin, and polyurethane.

The content of other resins, which may be optionally comprised, ispreferably 20 parts by mass or less, and more preferably 10 parts bymass or less, based on the total mass of the thermoplastic resincomprising the constituting unit derived from the dihydroxy compound ofthe above formula (1). If the content of other resins is too high, theremay be a case where compatibility is deteriorated and the transparencyof the resin composition is reduced.

(Physical Properties of Thermoplastic Resin)

The thermoplastic resin of the present invention (a molded body producedfrom the thermoplastic resin) has a saturated water absorption rate of0.39% by weight or less, and preferably 0.38% by weight or less. Thesaturated water absorption rate of a resin can be measured by the methoddescribed in the after-mentioned Examples.

The thermoplastic resin of the present invention (a molded body producedfrom the thermoplastic resin) has a YI value of 19 or less, preferably18 or less, and more preferably 17 or less. The YI value of a resin canbe measured by the method described in the after-mentioned Examples.

(Molded Body)

Using the thermoplastic resin of the present invention, a molded body(e.g., an optical element) can be produced. Such a molded body can bemolded, for example, by any given method, such as an injection moldingmethod, a compression molding method, an extrusion molding method, or asolution casting method. The optical element produced using thethermoplastic resin according to the embodiment is preferably used forlenses, prisms, etc.

Molded products produced by these methods are used for various types ofglazing uses, lenses for automobile lamps, lamp covers, optical lenses,OHP sheets, nameplates, display lights, etc. In addition, the filmsproduced by such methods are preferably used as Placell substrates orphase difference films for the intended use of flat panel displaysubstrates. For such Placell substrates, the films are used withoutbeing stretched. However, for the use as phase difference films, thefilms are subjected to stretch orientation, at least, in the uniaxialdirection, so that the phase difference films can have optimalbirefringence characteristics.

(Optical Lens)

Using the thermoplastic resin of the present invention, an optical lenscan be produced. The optical lens produced using the thermoplastic resinaccording to the embodiment has a high refractive index and is excellentin heat resistance. Hence, the optical lens can be used in the field inwhich expensive glass lenses with a high refractive index haveconventionally been used, such as a telescope, binoculars and atelevision projector, and thus, it is extremely useful. The optical lensis preferably used in the form of an aspherical lens, as necessary.Since a single aspherical lens is able to set the spherical aberrationto be substantially zero, it is not necessary to remove the sphericalaberration by a combination of multiple spherical lenses, and thus, itenables weight reduction and a reduction in production costs.Accordingly, such an aspherical lens is particularly useful as a cameralens, among optical lenses

The optical lens is formed by any given method such as an injectionmethod, a compression molding method, or an injection compressionmolding method. Using the thermoplastic resin according to theembodiment, an aspherical lens having a high refractive index and lowbirefringence, which is technically difficult to be processed from aglass lens, can be obtained more easily.

When the optical lens of the present invention is produced by injectionmolding, molding is preferably carried out under conditions of acylinder temperature of 230° C. to 270° C. and a metallic moldtemperature of 100° C. to 140° C. According to such molding conditions,an optical lens having excellent physical properties and also having thefunction of cutting the wavelength of an ultraviolet region can beobtained. Thus, when the produced optical lens is used as a lens fordigital cameras, the influence of ultraviolet ray on an image sensor canbe prevented without using an ultraviolet filter. In contrast, when theresin composition of the present invention is used as an ultravioletfilter, since it has extremely high transparency, the image quality ofthe taken photographs is not deteriorated, and clear photographs can betaken.

Moreover, since the resin of the embodiment has high fluidity, it can bea thin and small optical lens having a complicated shape. With regard tothe specific size of the lens, the thickness of the central portion is0.05 to 3.0 mm, more preferably 0.05 to 2.0 mm, and further preferably0.1 to 2.0 mm. In addition, the diameter is 1.0 mm to 20.0 mm, morepreferably 1.0 to 10.0 mm, and further preferably 3.0 to 10.0 mm.

On the surface of the optical lens of the present invention, a coatinglayer such as an anti-reflection layer or a hard coat layer may beestablished, as necessary. The anti-reflection layer may be a singlelayer or multiple layers. It may also be an organic matter or aninorganic matter, but it is preferably an inorganic matter. Specificexamples include oxides or fluorides, such as silicon oxide, aluminumoxide, zirconium oxide, titanium oxide, cerium oxide, magnesium oxide ormagnesium fluoride. Moreover, the optical lens of the present inventionmay also be molded by any given method such as metal molding, cutting,polishing, laser processing, electrical discharge machining, or edging.Among these methods, metal molding is more preferable.

In order to reduce the mixing of foreign matters into the optical lensto the minimum, the molding environment must be a low-dust environment,and the environment has a class of preferably 6 or less, and morepreferably 5 or less.

(Optical Film)

Using the thermoplastic resin of the present invention, an optical filmcan be produced. Since the optical film produced using the thermoplasticresin according to the embodiment is excellent in transparency and heatresistance, it is preferably used for films for liquid crystalsubstrates, optical memory cards, etc.

It is to be noted that the “sheet” generally means a thin and flatproduct, the thickness of which is relatively small, in consideration ofthe length and width thereof, and that the “film” is a thin and flatproduct, the thickness of which is extremely small, in consideration ofthe length and width thereof, wherein the highest thickness isarbitrarily limited, and it is generally supplied in the form of a roll.In the present description, however, the “sheet” is not clearlydistinguished from the “film.” and they are both used to have the samemeaning.

The film formed from the thermoplastic resin of the present inventionhas good heat resistance and hue. For example, the resin composition isdissolved in an organic solvent such as methylene chloride,tetrahydrofuran or dioxane, and is then molded into a casting film.Thereafter, a gas barrier film or a solvent-resistant film is applied toboth sides of this film. Otherwise, together with a transparentconductive film or a polarizing plate, the film is preferably used as afilm for liquid crystal substrates (Placell substrate), or as a liquidcrystal display film such as a phase difference film. Specifically, thefilm can be advantageously used for various display devices such as atablet, a smart phone or a handy terminal.

EXAMPLES

Hereinafter, the present invention will be more specifically describedin the following examples. However, these examples are not intended tolimit the scope of the present invention.

1. Production Example of Polycarbonate Resin

A polycarbonate resin was evaluated by the following methods.

1) Polystyrene-Relative Weight Average Molecular Weight (Mw):

Tetrahydrofuran was used as a developing solvent, and a calibrationcurve was produced according to GPC, using standard polystyrene having aknown molecular weight (molecular weight distribution: 1). Based on theproduced calibration curve, the polystyrene-relative weight averagemolecular weight (Mw) was calculated from the retention time in GPC.

2) HPLC Measurement Conditions: Contents of BHEBN, Compound (A),Compound (B), and Compound (C)

-   -   LC measurement device: LC-2010A, manufactured by Shimadzu        Corporation    -   Column: YMC-Pack ODS-AM (4.6 mm in diameter×250 mm, particle        diameter: 5 μm)    -   Column temperature: 25° C.    -   Mobile phase solvent: Pure water/acetonitrile (acetonitrile        20%→95%)    -   Flow rate: 1.0 mL/min    -   Detection method: UV (detection wavelength: 254 nm)

In the measurement results, the symbol % indicates the area percentagevalue corrected by removing the solvent in HPLC, unless otherwisespecified.

3) Saturated Water Absorption Rate (%):

Using a disk (diameter: 40 mm, thickness: 3 mm) prepared by pressmolding the obtained polycarbonate resin, the saturated water absorptionrate was measured in accordance with JIS-K-7209.

4) YI:

A quartz glass cell was filled with pellets, and the YI value was thenmeasured using a color-difference meter (SE-2000, manufactured by NIPPONDENSHOKU INDUSTRIES. Co., LTD.) by a reflection measurement method inaccordance with JIS K 7373: 2006.

Synthetic Example 1

18.082 g of 1,1′-bi-2-Naphthol (0.063 moles), 12.652 g of ethylenecarbonate (0.144 moles), 1.5 g of potassium carbonate, and 20 g oftoluene were added to a glass reactor equipped with a stirrer, a coolerand a thermometer, and the temperature was then increased to 115° C. sothat the mixture was converted to a slurry state. Thereafter, the slurrywas reacted at 115° C. for 10 hours. Subsequently, the reaction mixturewas diluted by addition of 18 g of toluene, and an organic solvent phasecomprising the reaction mixture was then washed with 30 g of 10% sodiumhydroxide solution. The organic solvent phase was further washed untilthe washing solution became neutral. After completion of the waterwashing, the organic solvent phase was refluxed and dehydrated, and wasthen cooled to room temperature, followed by filtration and drying, soas to obtain 2,2′-bis(2-hydroxyethoxy)-1,1′-binaphthalene as a whitecrystal. HPLC purity was 99.66%, the content of the compound (A) was 250ppm, the content of the compound (B) was 30 ppm, and the compound (C)was not detected (BHEBN-1).

Synthetic Example 2

The reaction was carried out in the same manner as that of SyntheticExample 1, with the exception that the reaction was carried out at 110°C. for 10 hours, to obtain 2,2′-bis(2-hydroxyethoxy)-1,1′-binaphthaleneas a white crystal. HPLC purity was 99.76%, the content of the compound(A) was 210 ppm, and the compound (B) and the compound (C) were notdetected (BHEBN-2).

Synthetic Example 3

The reaction was carried out in the same manner as that of SyntheticExample 1, with the exception that the reaction was carried out at 105°C. for 12 hours, to obtain 2,2′-bis(2-hydroxyethoxy)-1,1′-binaphthaleneas a white crystal. HPLC purity was 98.76%, the content of the compound(A) was 480 ppm, the content of the compound (B) was 950 ppm, and thecontent of the compound (C) was 200 ppm (BHEBN-3).

The results obtained by analyzing the dihydroxy compounds obtained inSynthetic Examples 1 to 3 are shown in Table 1.

TABLE 1 HPLC Com- Com- Com- purity pound (A) pound (B) pound (C)Synthetic BHEBN-1 99.66% 250 ppm  30 ppm — Ex. 1 Synthetic BHEBN-299.76% 210 ppm — — Ex. 2 Synthetic BHEBN-3 98.76% 480 ppm 950 ppm 200ppm Ex. 3

Example 1

20.360 g of BHEBN-1 (0.054 moles) obtained in Synthetic Example 1,32.954 g of 9,9-bis(4-(2-hydroxyethoxy)phenyl)fluorene (0.075 moles)(hereinafter also abbreviated as “BPEF”), 28.521 g of diphenyl carbonate(0.133 moles) (hereinafter also abbreviated as “DPC”), and 6μmoles/moles sodium hydrogen carbonate used as a catalyst (wherein thesodium hydrogen carbonate was indicated with the number of moles basedon a sum of BHEBN-1 and BPEF, and was added in the state of a 0.1 wt %aqueous solution) were added into a 500-mL glass reactor equipped with astirrer and a distillation apparatus. Thereafter, the reactor was heatedto 180° C. under 760 Torr in a nitrogen atmosphere. Ten minutes afterinitiation of the heating, complete dissolution of the raw materials wasconfirmed, and the stirring of the mixed solution was then initiated.Thereafter, stirring was carried out for 110 minutes under the sameconditions as described above. During this operation, it was confirmedthat phenol generated as a by-product started to be distillated.Subsequently, the degree of vacuum was adjusted to 20 Torr, and at thesame time, the temperature was increased to 200° C. at a rate of 60°C./hr. Thereafter, the temperature was retained at 200° C. for 20minutes, and the reaction was carried out. Thereafter, the temperaturewas increased to 230° C. at a rate of 75° C./hr. Ten minutes aftercompletion of the temperature rising, while the temperature was retainedat 230° C., the degree of vacuum was reduced to 1 Torr over 1 hour.After that, the temperature was increased to 240° C. at a rate of 60°C./hr, and the reaction was further carried out under stirring for 20minutes. After completion of the reaction, the inside of the reactor wasreturned to ordinary pressure by introducing nitrogen therein, and thegenerated polycarbonate resin was then collected. The evaluation of theobtained resin is shown in Table 2.

Example 2

19.787 g of BHEBN-1 (0.053 moles) obtained in Synthetic Example 1,39.756 g of 9,9-bis(4-(2-hydroxyethoxy)-3-phenylphenyl)fluorene (0.067moles) (hereinafter also abbreviated as “BPPEF”), 26.078 g of DPC (0.122moles), and 6 μmoles/moles sodium hydrogen carbonate used as a catalyst(wherein the sodium hydrogen carbonate was indicated with the number ofmoles based on a sum of BHEBN-1 and BPPEF, and was added in the state ofa 0.1 wt % aqueous solution) were added into a glass reactor equippedwith a stirrer and a distillation apparatus. Thereafter, the reactor washeated to 180° C. under 760 Torr in a nitrogen atmosphere. Ten minutesafter initiation of the heating, complete dissolution of the rawmaterials was confirmed, and the stirring of the mixed solution was theninitiated. Thereafter, stirring was carried out for 110 minutes underthe same conditions as described above. During this operation, it wasconfirmed that phenol generated as a by-product started to bedistillated. Subsequently, the degree of vacuum was adjusted to 20 Torr,and at the same time, the temperature was increased to 200° C. at a rateof 60° C./hr. Thereafter, the temperature was retained at 200° C. for 20minutes, and the reaction was carried out. Thereafter, the temperaturewas increased to 230° C. at a rate of 75° C./hr. Ten minutes aftercompletion of the temperature rising, while the temperature was retainedat 230° C., the degree of vacuum was reduced to 1 Torr over 1 hour.After that, the temperature was increased to 240° C. at a rate of 60°C./hr, and the reaction was further carried out under stirring for 20minutes. After completion of the reaction, the inside of the reactor wasreturned to ordinary pressure by introducing nitrogen therein, and thegenerated polycarbonate resin was then collected. The evaluation of theobtained resin is shown in Table 2.

Example 3

The reaction was carried out in the same manner as that of Example 1,with the exception that BHEBN-2 obtained in Synthetic Example 2 wasused. The evaluation of the obtained resin is shown in Table 2.

Example 4

The reaction was carried out in the same manner as that of Example 2,with the exception that BHEBN-2 obtained in Synthetic Example 2 wasused. The evaluation of the obtained resin is shown in Table 2.

Example 5

The reaction was carried out in the same manner as that of Example 1,with the exception that 14.450 g of BHEBN-1 (0.039 moles) obtained inSynthetic Example 1, 40.000 g of9,9-bis(4-(2-hydroxyethoxy)phenyl)fluorene (BPEF) (0.091 moles), 28.521g of diphenyl carbonate (DPC) (0.133 moles), and 6 μmoles/moles sodiumhydrogen carbonate serving as a catalyst (w % herein the sodium hydrogencarbonate was indicated with the number of moles based on a sum ofBHEBN-1 and BPEF, and was added in the state of a 0.1 wt % aqueoussolution) were used as raw materials. The evaluation of the obtainedresin is shown in Table 2.

Example 6

The reaction was carried out in the same manner as that of Example 1,with the exception that 23.000 g of BHEBN-1 (0.061 moles) obtained inSynthetic Example 1, 18.000 g of BPEF (0.041 moles), 22.500 g of DPC(0.105 moles), and 6 μmoles/moles sodium hydrogen carbonate serving as acatalyst (wherein the sodium hydrogen carbonate was indicated with thenumber of moles based on a sum of BHEBN-1 and BPEF, and was added in thestate of a 0.1 wt % aqueous solution) were used as raw materials. Theevaluation of the obtained resin is shown in Table 2.

Example 7

The reaction was carried out in the same manner as that of Example 2,with the exception that 12.000 g of BHEBN-1 (0.032 moles) obtained inSynthetic Example 1, 44.000 g of9,9-bis(4-(2-hydroxyethoxy)-3-phenylphenyl)fluorene (BPPEF) (0.074moles), 23.400 g of DPC (0.109 moles), and 6 μmoles/moles sodiumhydrogen carbonate serving as a catalyst (wherein the sodium hydrogencarbonate was indicated with the number of moles based on a sum ofBHEBN-1 and BPPEF, and was added in the state of a 0.1 wt % aqueoussolution) were used as raw materials.

Example 8

The reaction was carried out in the same manner as that of Example 2,with the exception that 20.000 g of BHEBN-1 (0.053 moles) obtained inSynthetic Example 1, 21.000 g of BPPEF (0.036 moles), 19.600 g of DPC(0.091 moles), and 6 μmoles/moles sodium hydrogen carbonate serving as acatalyst (wherein the sodium hydrogen carbonate was indicated with thenumber of moles based on a sum of BHEBN-1 and BPPEF, and was added inthe state of a 0.1 w % aqueous solution) were used as raw materials.

Comparative Example 1

The reaction was carried out in the same manner as that of Example 1,with the exception that BHEBN-3 obtained in Synthetic Example 3 wasused. The evaluation of the obtained resin is shown in Table 2.

Comparative Example 2

The reaction was carried out in the same manner as that of Example 2,with the exception that BHEBN-3 obtained in Synthetic Example 3 wasused. The evaluation of the obtained resin is shown in Table 2.

Comparative Example 3

18.120 g of BHEBN-3 (0.048 moles) obtained in Synthetic Example 3,29.899 g of 9,9-bis(4-(2-hydroxyethoxy)phenyl)fluorene (BPEF) (0.068moles), 25.600 g of diphenyl carbonate (DPC) (0.120 moles), and 6μmoles/moles sodium hydrogen carbonate used as a catalyst (wherein thesodium hydrogen carbonate was indicated with the number of moles basedon a sum of BHEBN-1 and BPEF, and was added in the state of a 0.1 wt %aqueous solution) were added into a glass reactor equipped with astirrer and a distillation apparatus. Thereafter, the reactor was heatedto 180° C. under 760 Tort in a nitrogen atmosphere. Ten minutes afterinitiation of the heating, complete dissolution of the raw materials wasconfirmed, and the stirring of the mixed solution was then initiated.Thereafter, stirring was carried out for 110 minutes under the sameconditions as described above. During this operation, it was confirmedthat phenol generated as a by-product started to be distillated.Subsequently, the degree of vacuum was adjusted to 20 Torr, and at thesame time, the temperature was increased to 200° C. at a rate of 60°C./hr. Thereafter, the temperature was retained at 200° C. for 20minutes, and the reaction was carried out. Thereafter, the temperaturewas increased to 230° C. at a rate of 75° C./hr. Ten minutes aftercompletion of the temperature rising, while the temperature was retainedat 230° C., the degree of vacuum was reduced to 1 Torr over 1 hour.After that, the temperature was increased to 240° C. at a rate of 60°C./hr, and the reaction was further carried out under stirring for 40minutes. After completion of the reaction, the inside of the reactor wasreturned to ordinary pressure by introducing nitrogen therein, and thegenerated polycarbonate resin was then collected. The evaluation of theobtained resin is shown in Table 2.

Comparative Example 4

17.800 g of BHEBN-1 (0.048 moles) obtained in Synthetic Example 1,36.420 g of 9,9-bis(4-(2-hydroxyethoxy)-3-phenylphenyl)fluorene (0.062moles) (hereinafter also abbreviated as “BPPEF”), 23.646 g of DPC (0.110moles), and 6 μmoles/moles sodium hydrogen carbonate used as a catalyst(wherein the sodium hydrogen carbonate was indicated with the number ofmoles based on a sum of BHEBN-1 and BPPEF, and was added in the state ofa 0.1 wt % aqueous solution) were added into a glass reactor equippedwith a stirrer and a distillation apparatus. Thereafter, the reactor washeated to 180° C. under 760 Torr in a nitrogen atmosphere. Ten minutesafter initiation of the heating, complete dissolution of the rawmaterials was confirmed, and the stirring of the mixed solution was theninitiated. Thereafter, stirring was carried out for 110 minutes underthe same conditions as described above. During this operation, it wasconfirmed that phenol generated as a by-product started to bedistillated. Subsequently, the degree of vacuum was adjusted to 20 Torr,and at the same time, the temperature was increased to 200° C. at a rateof 60° C./hr. Thereafter, the temperature was retained at 200° C. for 20minutes, and the reaction was carried out. Thereafter, the temperaturewas increased to 230° C. at a rate of 75° C./hr. Ten minutes aftercompletion of the temperature rising, while the temperature was retainedat 230° C., the degree of vacuum was reduced to 1 Torr over 1 hour.After that, the temperature was increased to 240° C. at a rate of 60° °C./hr, and the reaction was further carried out under stirring for 40minutes. After completion of the reaction, the inside of the reactor wasreturned to ordinary pressure by introducing nitrogen therein, and thegenerated polycarbonate resin was then collected. The evaluation of theobtained resin is shown in Table 2.

The composition, Mw (weight average molecular weight), saturated waterabsorption rate, and YI of the resins obtained in the above-describedexamples and comparative examples are shown in Table 2.

TABLE 2 Copolymerization ratio (mole %) Saturated water BHEBN BHEBN BPEFBPPEF Mw absorption rate (wt %) Pellet YI Example 1 BHEBN-1 42 58 —43000 0.37 16 Example 2 BHEBN-1 44 — 56 53000 0.38 14 Example 3 BHEBN-242 58 — 44000 0.35 18 Example 4 BHEBN-2 44 — 56 54000 0.36 17 Example 5BHEBN-1 30 70 — 43000 0.38 14 Example 6 BHEBN-1 60 40 — 44000 0.39 15Example 7 BHEBN-1 30 — 70 53000 0.38 19 Example 8 BHEBN-1 60 — 40 540000.39 18 Comp. Ex. 1 BHEBN-3 42 58 — 40000 0.41 19 Comp. Ex. 2 BHEBN-3 44— 56 50000 0.42 18 Comp. Ex. 3 BHEBN-3 42 58 — 45000 0.40 21 Comp. Ex. 4BHEBN-3 44 — 56 55000 0.41 22BPEF: 9,9-bis(4-(2-hydroxyethoxy)phenyl)fluoreneBPPEF: 9,9-bis(4-(2-hydroxyethoxy)-3-phenylphenyl)fluoreneBHEBN: 2,2′-bis(2-hydroxyethoxy)-1,1′-binaphthaleneBPA: 2,2-bis(4-hydroxyphenyl)propaneDPC: diphenyl carbonate

It is found that the polycarbonate resins obtained in Examples 1 to 8,in which raw materials comprising reduced contents of the compounds ofthe formulae (A) to (C) were used, have a low saturated water absorptionrate, such as 0.35% to 0.39% by weight.

It is found that the saturated water absorption rate of the resins issignificantly decreased, particularly when a raw material (BHEBN-2)comprising significantly reduced contents of the compounds of theformulae (A) to (C) was used (Examples 3 and 4).

On the other hand, it is found that the polycarbonate resins obtained inComparative Examples 1 to 4, in which the contents of the compounds ofthe formulae (A) to (C) were large, have a high saturated waterabsorption rate, such as 0.40% by weight or more.

Moreover, it was found that, in Examples 1 to 8 in which raw materialscomprising reduced contents of the compounds of the formulae (A) to (C)were used, an increase in the molecular weight of the obtainedpolycarbonate resin and excellent hue (i.e., a low YI value) wereobtained, in comparison to Comparative Examples 1 and 2 in which thedihydroxy compound having the same structure was used.

Furthermore, the carbonate resins of Examples 1 to 4, 5, and 7, in whichthe molar ratio between the dihydroxy compound of the formula (1) andthe dihydroxy compound of the formula (2) (constituting unit(1)′/constituting unit (2)′) was 30/70 to 50/50 (in particular. Examples1 to 4, in which the molar ratio was 40/60 to 50/50) have a reducedsaturated water absorption rate, in comparison to the carbonate resinsof Examples 6 and 8, in which the dihydroxy compound having the samestructure was used.

Further, it is confirmed that, in Comparative Examples 3 and 4,high-molecular-weight polycarbonate resins were obtained by prolongingthe polymerization reaction time, in comparison to Comparative Examples1 and 2, but the polycarbonate resins of Comparative Examples 3 and 4were inferior to those of Comparative Examples 1 and 2, in terms of hue(i.e., a high YI value).

2. Production Example of Film

A film was evaluated by the following methods.

(1) Total Light Transmittance and Haze

Total light transmittance and haze were measured using a hazemeter(“HM-150,” manufactured by MURAKAMI COLOR RESEARCH LABORATORY CO.,Ltd.), in accordance with JIS K-7361-1: 1997 and JIS K-7136: 2000.

(2) Glass Transition Temperature

Glass transition temperature was measured using a differential thermalscanning calorimeter (DSC) (measuring device: DSC7000X, manufactured byHitachi High-Tech Science Corporation DSC7000X).

(3) Surface Shape

The surface shape of a light diffusion film was evaluated usingarithmetic average roughness. Arithmetic average roughness was obtainedby preparing a roughness curve using a small surface roughness measuringdevice (“SURFTEST SJ-210,” manufactured by Mitutoyo Corporation), andthen calculating the roughness as follows. That is, the range of areference length (1) (average line direction) was extracted from theprepared roughness curve, and thereafter. X axis was set in thedirection of an average line of this extracted portion, whereas Y axiswas set in a direction perpendicular to the X axis. When the roughnesscurve was represented by y=f(x), the value (μm) obtained by thefollowing expression was defined as an arithmetic average roughness(Ra). Herein, the term “reference length (1) (average line direction)”is used to mean the reference length of a roughness parameter accordingto JIS B 0601: 2001 (ISO 4287: 1997).

${Ra} = {\frac{1}{\ell}{\int_{0}^{\ell}{{{f(x)}}\ {dx}}}}$(5) Refractive Index

The refractive index of a film having a thickness of 0.1 mm was measuredusing an Abbe's refractometer according to the method of JIS-K-7142 (23°C., wavelength: 589 nm).

(6) Abbe Number (ν)

The refractive indexes of a film having a thickness of 0.1 mm at 23° C.at wavelengths of 486 nm, 589 nm and 656 nm were measured using anAbbe's refractometer, and thereafter, the Abbe number (ν) thereof wasfurther calculated according to the following formula:ν=(nD−1)/(nF−nC)

nD: refractive index at a wavelength of 589 nm

nC: refractive index at a wavelength of 656 nm

nF: refractive index at a wavelength of 486 nm

(7) Melt Volume Rate (MVR)

The obtained resin was vacuum-dried at 120° C. for 4 hours, andthereafter, the melt volume rate (MVR) of the resin was measured usingMelt Indexer T-111 manufactured by Toyo Seiki Seisaku-sho, Ltd., underconditions of a temperature of 260° C. and a load of 2160 g.

Example 9

The reaction was carried out in the same manner as that of Example 1,with the exceptions that the amounts of BHEBN, BPEF, diphenyl carbonate(DPC), and sodium hydrogen carbonate were changed to 6.20 kg (16.56moles), 10.00 kg (22.80 moles), 8.67 kg (40.46 moles), and 1.98×10⁻² g(2.36×10⁻⁴ moles), respectively, and that the size of the reactor waschanged to 50 L. After completion of the reaction, nitrogen wasintroduced into the reactor, and the generated polycarbonate resin wasextracted, while it was pelletized.

The obtained pellets were subjected to melt extrusion at 280° C., usinga 26-mm biaxial extruder and a T die. The extruded melted film wasnipped between a first cooling roll made of silicon rubber, having adiameter of 200 mm, and a second cooling roll made of metal, having adiameter of 200 mm, which had been subjected to mat-processing(arithmetic average roughness of surface: 3.2 μm). The mat pattern wasformed on the surface of the film, and the film was then cooled. Then,the film was further passed through a third cooling roll made of metal,the surface of which had a mirror structure, and while the film wasdrawn by a draw-off roll, it was molded into a film, one surface ofwhich was matted. During this operation, the temperature of the firstcooling roll was set at 40° C., the temperature of the second coolingroll was set at 130° C., the temperature of the third cooling roll wasset at 130° C., and the speed of the cooling rolls was adjusted, so thatthe arithmetic average roughness of the film surface was adjusted to be3.0 μm.

The evaluation results of the film obtained in Example 9 are shown inTable 3.

TABLE 3 Example 9 Film thickness (μm) 220 Haze (%) 88.6 Total lighttransmittance (%) 86.1 Arithmetic average roughness (μm) 3.0 Glasstransition temperature (° C.) 134 MVR 260° C. cm³/10 min 32 Abbe number21.5 Refractive index 1.651

From the above Table 3, it is confirmed that the film produced using thepolycarbonate resin of the present invention has high haze and excellenttransparency, and further exhibits a low Abbe number and a highrefractive index.

3. Production Example of Optical Lens

Ten thin molded products were produced using a metallic mold capable offorming a lens having a curvature radius on the convex surface of 5.73mm, a curvature radius on the concave surface of 3.01 mm, a diameter of4.5 mm, a diameter of a lens portion of 3 mm, and a central thickness ofa lens of 0.20 mm, and employing an injection molding machine ROBOSHOTS-2000i30A, manufactured by FANUC CORPORATION, at a resin temperature of260° C., a metallic mold temperature Tg of −5° C., and a sustainingpressure of 600 kgf/cm².

The obtained optical lenses were evaluated by the following methods.

[Evaluation of Birefringence]

The birefringence of the obtained molded products was measured using abirefringence meter (KOBRA (registered trademark)-CCD/X; manufactured byOji Scientific Instruments), and a comparison was then made in terms ofthe value of retardation in the central portion of a lens at ameasurement wavelength of 650 nm. The smaller the retardation value, themore excellent the low birefringence property that can be obtained. Aretardation value of less than 20 was evaluated to be A, a retardationvalue of 20 or more and less than 40 was evaluated to be B, aretardation value of 40 or more and less than 60 was evaluated to be C,and a retardation value of 60 or more was evaluated to be D.

[Evaluation of Weld Line]

The obtained molded products were each observed under a microscope, andthe length of a weld line generated in an anti-gate direction wasmeasured. The length of the weld line that was less than 0.1 mm wasevaluated to be A, 0.1 mm or more and less than 0.3 mm was evaluated tobe B, 0.3 mm or more and less than 0.5 mm was evaluated to be C, and 0.5mm or more was evaluated to be D.

Example 10

The polycarbonate resin obtained in Example 1 was vacuum-dried at 120°C. for 1 hour to produce an injection molded product. The results of thebirefringence evaluation and weld line evaluation of the obtained moldedproduct are shown in Table 4.

Example 11

The polycarbonate resin obtained in Example 2 was vacuum-dried at 120°C. for 1 hour to produce an injection molded product. The results of thebirefringence evaluation and weld line evaluation of the obtained moldedproduct are shown in Table 4.

Example 12

The polycarbonate resin obtained in Example 3 was vacuum-dried at 120°C. for 1 hour to produce an injection molded product. The results of thebirefringence evaluation and weld line evaluation of the obtained moldedproduct are shown in Table 4.

Example 13

The polycarbonate resin obtained in Example 4 was vacuum-dried at 120°C. for 1 hour to produce an injection molded product. The results of thebirefringence evaluation and weld line evaluation of the obtained moldedproduct are shown in Table 4.

Comparative Example 5

The polycarbonate resin obtained in Comparative Example 1 wasvacuum-dried at 120° C. for 1 hour to produce an injection moldedproduct. The results of the birefringence evaluation and weld lineevaluation of the obtained molded product are shown in Table 4.

Comparative Example 6

The polycarbonate resin obtained in Comparative Example 2 wasvacuum-dried at 120° C. for 1 hour to produce an injection moldedproduct. The results of the birefringence evaluation and weld lineevaluation of the obtained molded product are shown in Table 4.

Comparative Example 7

The polycarbonate resin obtained in Comparative Example 3 wasvacuum-dried at 120° C. for 1 hour to produce an injection moldedproduct. The results of the birefringence evaluation and weld lineevaluation of the obtained molded product are shown in Table 4.

Comparative Example 8

The polycarbonate resin obtained in Comparative Example 4 wasvacuum-dried at 120° C. for 1 hour to produce an injection moldedproduct. The results of the birefringence evaluation and weld lineevaluation of the obtained molded product are shown in Table 4.

Comparative Example 9

An injection molded product was produced using pellets of apolycarbonate resin (lupilon H-4000 manufactured by MitsubishiEngineering-Plastics Corporation; a polycarbonate resin consisting ofbisphenol A (BPA-HOMO-PC)). The results of the birefringence evaluationand weld line evaluation of the obtained molded product are shown inTable 4.

TABLE 4 Birefringence Evaluation of weld line Example 10 B A Example 11B A Example 12 B B Example 13 B B Comp. Example 5 B C Comp. Example 6 CD Comp. Example 7 B D Comp. Example 8 B D Comp. Example 9 D A

From the above Table 4, the optical lenses produced using thepolycarbonate resin of the present invention had low birefringence(evaluation of B).

Moreover, the optical lenses of the present invention had a short weldline (evaluation of A or B). It is assumed that this is because thepolycarbonate resin of the present invention has a good saturated waterabsorption rate and also because generation of decomposition gas issuppressed when the polycarbonate resin of the present invention isused. In general, the weld line is influenced by factors such asaccumulation of gas in a metallic mold, molding conditions (a moldingtemperature, a metallic mold temperature, a pressure, etc.), andgeneration of decomposition gas. It is assumed that the polycarbonateresin of the present invention is able to reduce the abundance of OH(water, aromatic OH, etc.) in the system by using raw materials in whichthe contents of the compounds of the formulae (A) to (C) are reduced,and that this would lead to suppression of transesterification, so thatgeneration of decomposition gas could be suppressed.

Accordingly, by using the polycarbonate resin of the present invention,the length of the weld line can be reduced without performing theconventional measures for reducing the weld line length (e.g., measuresusing metallic molds (e.g., the establishment of a vent, the adjustmentof the thickness of a metallic mold, the adjustment of a gate, etc.)),and therefore, the polycarbonate resin of the present invention isadvantageous in terms of production costs and the easiness of theproduction.

Several embodiments of the present invention are described above.However, these embodiments are provided as examples, and thus, are notintended to limit the scope of the present invention. These novelembodiments can be carried out in various other forms, and variousabbreviations, substitutions, and alternations can also be carried outin a range in which such modification is not deviated from the gist ofthe present invention. These embodiments and the modifications thereofare included in the scope or gist of the invention, and are alsoincluded in the invention described in claims and in a scope equivalentthereto.

What claimed is:
 1. A dihydroxy compound comprising a dihydroxy compoundrepresented by the following formula (1), wherein the total weight of acompound represented by the following formula (A), a compoundrepresented by the following formula (B), and a compound represented bythe following formula (C) in the dihydroxy compound is 1 ppm or more and1,500 ppm or less, based on 100 parts by weight of the dihydroxycompound represented by the formula (1):

wherein X represents an alkylene group containing 1 to 4 carbon atoms,


2. The compound according to claim 1, wherein the total weight of acompound represented by the following formula (A) and a compoundrepresented by the following formula (B) in the dihydroxy compound is1,000 ppm or less, based on 100 parts by weight of the dihydroxycompound represented by the formula (1).
 3. The compound according toclaim 1, wherein the weight of the compound represented by the formula(A) in the dihydroxy compound is 300 ppm or less, based on 100 parts byweight of the dihydroxy compound represented by the formula (1).
 4. Thecompound according to claim 1, wherein the weight of the compoundrepresented by the formula (B) in the dihydroxy compound is 500 ppm orless, based on 100 parts by weight of the dihydroxy compound representedby the formula (1).
 5. The compound according to claim 1, wherein theweight of the compound represented by the formula (C) in the dihydroxycompound is 100 ppm or less, based on 100 parts by weight of thedihydroxy compound represented by the formula (1).
 6. The compoundaccording to claim 1, wherein the purity of the dihydroxy compoundrepresented by the formula (1) is 99% or more.
 7. The compound accordingto any claim 1, wherein the dihydroxy compound represented by theformula (1) is at least one selected from2,2′-bis(1-hydroxymethoxy)-1,1′-binaphthalene,2,2′-bis(2-hydroxyethoxy)-1,1′-binaphthalene,2,2′-bis(3-hydroxypropyloxy)-1,1′-binaphthalene, and2,2′-bis(4-hydroxybutoxy)-1,1′-binaphthalene.
 8. The compound accordingto claim 1, for use as a raw material for a thermoplastic resin.
 9. Araw material for a thermoplastic resin which comprises as a dihydroxycomponent the dihydroxy compound according to claim 1, wherein thepercentage of the dihydroxy compound of the formula (1) is 1 to 100 mol%, based on 100 mol % of the dihydroxy compound used as a raw materialfor a thermoplastic resin.
 10. The raw material according to claim 9,which further comprises as the dihydroxy component a compoundrepresented by the following formula (2):

wherein R₁ to R₄ are each independently selected from the groupconsisting of a hydrogen atom, an alkyl group containing 1 to 20 carbonatoms, an alkoxy group containing 1 to 20 carbon atoms, a cycloalkylgroup containing 5 to 20 carbon atoms, a cycloalkoxy group containing 5to 20 carbon atoms, an aryl group containing 6 to 20 carbon atoms, anaryloxy group containing 6 to 20 carbon atoms, and a halogen atom; Xeach independently represents an alkylene group containing 2 to 8 carbonatoms; and n each independently represents an integer of 1 to
 5. 11. Theraw material according to claim 9, wherein the thermoplastic resin isselected from the group consisting of a polycarbonate resin, a polyesterresin, and a polyester carbonate resin.
 12. The raw material accordingto claim 9, wherein the thermoplastic resin is a polycarbonate resin.13. The raw material according to claim 9, which further comprisescarbonic acid diester.
 14. The raw material according to claim 9,wherein the saturated water absorption rate of the thermoplastic resinis 0.39% by weight or less.
 15. The raw material according to claim 9,wherein the weight average molecular weight of the thermoplastic resinis 35,000 to 70,000.
 16. An optical element which is characterized inthat it uses a thermoplastic resin obtained from the compound accordingto claim
 1. 17. An optical lens which is characterized in that it uses athermoplastic resin obtained from the compound according to claim
 1. 18.An optical film which is characterized in that it uses a thermoplasticresin obtained from the compound according to claim
 1. 19. An opticalelement which is characterized in that it uses a thermoplastic resinobtained from the raw material according to claim
 9. 20. An optical lenswhich is characterized in that it uses a thermoplastic resin obtainedfrom the raw material according to claim
 9. 21. An optical film which ischaracterized in that it uses a thermoplastic resin obtained from theraw material according to claim 9.